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Date: Fri, 26 May 2023 18:13:38 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: David Howells <dhowells@redhat.com>
Cc: netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>, Eric
 Dumazet <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Willem de
 Bruijn <willemdebruijn.kernel@gmail.com>, David Ahern <dsahern@kernel.org>,
 Matthew Wilcox <willy@infradead.org>, Jens Axboe <axboe@kernel.dk>,
 linux-mm@kvack.org, linux-kernel@vger.kernel.org, Chuck Lever
 <chuck.lever@oracle.com>, Boris Pismenny <borisp@nvidia.com>, John
 Fastabend <john.fastabend@gmail.com>
Subject: Re: [PATCH net-next 10/12] tls/sw: Convert tls_sw_sendpage() to use
 MSG_SPLICE_PAGES
Message-ID: <20230526181338.03a99016@kernel.org>
In-Reply-To: <20230524153311.3625329-11-dhowells@redhat.com>
References: <20230524153311.3625329-1-dhowells@redhat.com>
	<20230524153311.3625329-11-dhowells@redhat.com>
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On Wed, 24 May 2023 16:33:09 +0100 David Howells wrote:
> Convert tls_sw_sendpage() and tls_sw_sendpage_locked() to use sendmsg()
> with MSG_SPLICE_PAGES rather than directly splicing in the pages itself.
> 
> [!] Note that tls_sw_sendpage_locked() appears to have the wrong locking
>     upstream.  I think the caller will only hold the socket lock, but it
>     should hold tls_ctx->tx_lock too.

Lock ordering, as you probably discovered. It is what it is :|

> +	if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL |
> +			       MSG_CMSG_COMPAT | MSG_SPLICE_PAGES |
> +			       MSG_SENDPAGE_NOTLAST | MSG_SENDPAGE_NOPOLICY))
> +		return -EOPNOTSUPP;

Now MSG_SENDPAGE_* can leak in thru the sendmsg() call?
Letting MSG_SENDPAGE_NOPOLICY in seems pretty suspicious, no?